Improvement in treating auriferous and argentiferous ores



Patented May 31, 186,4.

L. E. RIVOT.-

Treating Gres.

NA PETERS. Pnmo-Lilhognphor. wnshimuw. D c.

'M UH UNTTED STATES PATENT Ormea.

vLOUIS EDOUARD RIVO'I, OF PARIS, FRANCE, ASSIGNORTO JACQUES GAIL LARDON, OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT lN TREATING AURIFEROUS AND ARGENTIFEROUS ORES.

Specilieation forming part of Letters PatentrNo. 42,997, dated May ill, 1864.

To all whom vit may concern Be it known that I, Louis EDOUARD Rivo'r, professor at the Imperial School of Mines in Paris, in the Empire of France, have invented a new and useful Irocess of Heating Auriferous and Argentiferous Ores; and I hereby declare the following, taken in connection with the accompanying drawings, is a full, clear, and exact description of the same.

My invention relates more particularly to the treatment of such ores containing metallic sulphurets and also selenides, tellurides, and other composites containing arsenic and antimony, which, when treated according to the various methods of amalgam ation heretofore in use, fail to give favorable or practically good results; and my invention consists in a new method of treating such ores comprising the following operations: first, the grinding and porphyrization of ores mixed intimately with pyrites of iron or copper; second, the roasting of the ores by means of superheated steam 5 third, the amalgamation of the roasted ores; fourth, the separation of the amalgam; fifth, the compression of the amalgam 5 sixth, the distillation of the mercury; seventh, the fusion of the precious metal ores.

I shall now referto each operation separately, and describe the manner in which the same is Aor may be carried into effect.

First. The grinding and porphyrization of the ores mixed with pyrites of iron or copperin proportions varying according to the composition of the ores. Any of the known machines or apparatus for grinding or triturating ores or other hard substances may be used for this operation.

Second. The roasting of the porphyrized ores mixed with pyrites by submitting the same to the action of steam superheated to a temperature somewhat above dark red, elfected in an oven or furnace, of an arrangement new in metallurgy and represented in the accompanying drawing, in which- Third. Figure l is a longitudinal elevation of the furnace; Fig. 2, a section on line l 2; Fig. 3, another section on line 3, 4, 5, and 6; Fig. 4, a transverse section on line 7 8, and Fig. 5 is an end view'on the side of the hre-chamber.

Above the sole A, and in the vicinity of the fire-chamber, there are arranged in the masonry voir, B, into which the roasted ores drop by passing through openings that are kept closed during the operation by means of cast-iron doors or plates. Immediately in rear of the furnace proper there is arranged the great condensing chamber c, wherein the arsenical and antimonial vapors or fumes are collected. 'Ihe arrangement shown for the grate and firechamber is most suited for wood. Other fuel capable of producing a long flame maybe used by applying slight modifications, which will readily suggest themselves. Ihe length and width of the sole are varied according to the charge of ore for each operation.

The furnace of which the above is a description presents thefollowin g peculiarity and novelty: rIhe ore being charged in thin layers upon the sole, the heating is effected by the reverberation of the roof, whose arch is followedby the iiame in its course from the iirebridge to the neck, while the roasting proper is produced by a jet of steam heated to dark red outside of and before being admitted into the reverberatory furnace. rIhc steam is then entered the furnace through five or six tuyerers, t, disposed on either side of the fire-bridge. It is generated and heated to the required temperature in any known or convenient apparatus.

The object of the roasting by means of steam is to expel the arsenic, antimony, tellurides, selenides, and the sulphur from the ore in a state of volatilizable combination and to leave upon the hearth or sole of the furnace the silver or gold in a metallic state, and the other metals as oxides, together with the earthy gangues. The furnace is charged at the side through openings E E', or the ore may be introduced through athopper arranged in the middle of the roof. Either plan may round stones.

be adopted as most convenient. The modus operandi is very simple. The supply of steam is regulated in such manner as that it shall form a continuous sheet interposed between the flame and the ore. From time to time it is necessary to work the ore, so as to successively expose all the particles to contact with and action of the steam. When the roasting -is completed, the ore is dropped down under the arched roof through the orifices h. The work is or may be continuous-that is to say, a new charge may be introduced as soon as the preceding charge is allowed to drop into the reservoir underneath the hearth.

The amalgamation of the roasted ore is effected in the manner as follows: The ore is put together with water and without addition of salt or of the magistral in large wooden barrels, revolving upon horizontal axles. These barrels should be arranged so that each can be rotated or stopped at will independently of the others. To the ore and water they contain are then added mercury and hard The object of this is to divide the mercury and to put it in prolonged and intimate contact with all the particles of the roasted ore, so that it may form amalgams withthe silver and gold. therein contained. When this is accomplished the barrels are rotated with less speed, and a fresh quantity of mercury is added for the purpose of uniting the amalgam in liquid the excess of mercury.

Fourth, separation of the amalgam: The barrels last referred to are emptied of their contents-t'. e., of the liquid amalgam, the me tallic oxides, and the earthy gangues. The sediments, which are composed of the oxides and the gan gues, are carefully washed to extract from them the minute globules of amalgam and mercury that are usually byl them retained. lf the ore contains copper, or if, for the purpose of wasting by means of steam above referred to, pyrites of copper have been used, then the sediments or mud should be preserved, as they constitute a valuable copper ore.

Fifth, compressiony of the amalgam: The liquid amalgam is compressed in bags, or ifa hydraulic press be used a pressure might be produced sufficient to squeeze the mercury globules, according to not combined with either gold or silver out through the pores of wood.

Sixth, distillation of mercury The result of the preceding operation, which is an amalgam nearly solid, is submitted to distillation, where by the mercury is volatilized in apparatus, collecting and condensing its vapors.

Seventh, fusion of the precious metal: The metal obtained by the preceding opeclose-textured cloth or silver and gold may be separated at the samel time.

Orcs containing bromide, chloride, or todide of silver may be treated according t-o the process above described, either alone or in combination with black sulphurous ores or with pyrites of iron or copper. .lhere is no loss whatsoever from volatilization, and the whole of the metalis reduced to a metallic state.

The last three operations may be effected by any process of amalgamation known and in apparatus familiar to metallurgists.

From the above description of my invenion it will be seen 'that the divers operations are either borrowed from processes well known or are devised in imitation of methods much less known. 'Thus the grinding and porphyrization of the ores. the separation ofthe amalgam from the residuary mud oxidated, the

compression ofthe amalgam, the distillation of with pyrites without the aid or intervention of reagents, such as salts and the'magistral, are operations heretofore unknown or untried in metallurgical, industry,v although they are known .in the science. Mentioning only what has been done in France, M. Regn'ault has studied many years ago the action of steam or metallic sulphurets, but his experiments have never been put in practice. More rel cently M. Cumenge (Ingnieur` des Mines) has published in the Annales des Mines the result of his laboratory experiments on the steam action.

M. Gumenge has made an important step in demonstrating the necessity of mixing the argentiferous and auriferous ores with pyrites. There was still an important and useful step to make, the steam being used practically by this new method, which consists in the use of superheated steam, and a new and convenient disposition of the reverberatory furnace. The superheating ofsteam renders its action more powerful and rapid, and does away with the objection heretofore urged against its employment, which was that of its sluggishness or slowness of action. Again, the amalgamation by trituration of the ore with mercury and without reagents has never been attempted in metallurgical operations, because of the silver and gold in ores could not be made directly to combine with mercury. This direct amalgamation is rendered possible only by the combining with it of the process of roasting described, the main object being the reduction of the gold and silver to a metallic state, allowing the other metals to pass off as oxides upon which mercury has no action.

Having thus fully described my said invention and the manner in which the same is or may be carriedinto effect, I claimration may be melted into ingots, and the,

1. rIhe roasting by means of superheated steam of auriferous and argentiferous ores', when combined or mixed with pyrites of iro or copper, substantially as set forth.

2. The general arrangement and construction of reverberatory furnaces adapted for the roasting of ores by means of steam superlIn testimony whereof I have signed my name heated, as hereinbefore described. to this specification before two subscribing 3. The process of amalgamation without witnesses.

reagents, substantially as hereinbefore de- L. E. RIVOT.

scribed, whereby the roasting of ores may be Witnesses:

rendered practicable and economical, as set E. RICHARDS.

forth. E. HERMAN GoULDs. 

